Examination of the Qbeta-replicase reaction by sucrose gradient and gel electrophoresis.

The products of an in vitro synthesis with the Qbeta replicase purified from Escherichia coli infected by the ribonucleic acid (RNA) bacteriophage Qbeta were examined by sucrose gradient centrifugation and polyacrylamide gel electrophoresis. It was found that, in contrast to sucrose gradients, gel electrophoresis clearly resolved four classes in the newly synthesized RNA. The product was found to contain mature Qbeta-RNA and small-molecular-weight RNA. In addition, two species were identified which corresponded to the structures found in vivo by Francke and Hofschneider and by Franklin. All of the participants implicated in RNA replication by in vivo studies have now been synthesized in vitro and isolated from the reaction mixture.